The present invention relates to the chemical cleaning arts. It finds particular application in conjunction with the removal of baked on residues from sterilizers, and will be described with particular reference thereto. It should be appreciated, however, that the invention is also applicable to the cleaning of residues from other processing equipment, such as pharmaceutical, food, and beverage equipment, and the like.
Steam sterilizers are generally operated at a pressure of about 2 kg/sq. cm (30 psi) and a temperature of around 130xc2x0 C. Over a period of time, the chamber walls become coated with a residue comprising baked on materials, such as boiler compounds, lint, debris, tape and packaging materials used to wrap medical devices being sterilized. These residues interfere with the efficient operation of the sterilizer or may be dislodged from the chamber walls and soil the sterilized items.
The baked on residues are difficult to remove. Mechanical methods have been used to remove the residue, but these are labor intensive. It takes approximately 6-8 hours to mechanically clean one sterilizer. In one method, the chamber walls are blasted with a stream of glass beads. An air compressor, which is parked outside the facility and connected to the glass bead equipment by a long air line, powers the equipment. The chamber is tented to contain the beads and dust generated. A ventilation hood, supplied by a separate air compressor, is worn by the operating technician. The surface of the chamber walls is often left in a roughened condition which is difficult to polish to a smooth finish.
In another method, a hand-held grinding/polishing wheel and an abrasive compound are used to remove the residue. The grinding wheel is usually powered by an air compressor, as for the glass bead method. The sterilizer is tented to contain dust generated in the process and breathing equipment is worn by the technician performing the cleaning. In the process, weld joints and studs in the sterilizer may be damaged and additional time is taken to repair the damage. For nickel plated sterilizer chambers, the polishing process may remove the thin nickel plating (typically around 0.5 millimeters in thickness, or less) exposing the underlying carbon steel to subsequent corrosion. On stainless steel sterilization chambers, damage to weld joints is a problem.
The present invention provides a new and improved system and method for cleaning baked-on residue from a vessel, which overcomes the above-referenced problems and others.
In accordance with one aspect of the present invention, a system for cleaning baked on organic and inorganic residues from a surface is provided. The system includes first and second chambers, which hold first and second cleaning fluids, respectively. Each of the chambers has an outlet for selectively withdrawing the cleaning fluids from the chambers, the outlets being selectively connectable with a first fluid line for transportating the cleaning fluid to the surface. Each of the chambers has an inlet which is selectively connectable with a second fluid line for selectively returning the cleaning fluids to the chamber after contacting the surface with the cleaning fluid. A selectively openable member connects the first and second chambers, which is selectively openable to allow the first cleaning fluid to mix with the second cleaning fluid. A means is provided for selectively opening the selectively openable member.
In accordance with another aspect of the present invention, a method of cleaning a surface is provided. The method includes:
a) delivering a first cleaning fluid from a first chamber to the surface,
b) returning the first cleaning fluid to the first chamber from the surface,
c) delivering a second cleaning fluid from a second chamber to the surface,
d) returning the second cleaning fluid to the second chamber from the surface, and
e) after steps a) through d), mixing the first cleaning fluid with the second cleaning fluid to form a mixture of neutral or near neutral pH.
In accordance with another aspect of the present invention, a method of cleaning a sterilizing chamber of a steam sterilizer of bake-on organic and inorganic residues is provided. The method includes removing organic residues by flushing the chamber with an organic residue cleaning fluid and, after removing the organic residue, draining the organic residue from the chamber. The method further includes removing inorganic residue by flushing the chamber with an inorganic residue cleaner and draining the inorganic residue cleaner from the chamber.
One advantage of the present invention is the provision of an easily portable cleaning system.
Another advantage of the present invention is that a sterilizer is cleaned and ready to be returned to service in about two to four hours.
Yet another advantage of the present invention is that the cleaning compositions are contained within the system and pose few hazards to operating technicians.
A further advantage of the present invention is that a neutralized product is formed after cleaning which may be disposed in the normal waste system.
A yet further advantage of the present invention is that the cleaning compositions have no significant impact on the nickel plate on the sterilizer walls.
A still yet further advantage of the present invention is that the system is adaptable to a variety of sterilizer shapes and sizes.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.